According to Wikipedia, Machine code or machine language is a set of instructions executed directly by a computer's central processing unit (CPU). Each instruction performs a very specific task, such as a load, a jump, or an ALU operation on a unit of data in a CPU register or memory. Every program ...

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1answer
190 views

Machine code JITs and the Execution Disable bit

How is runtime-generated machine-code (such as the output of a JIT), actually executed by the CPU if the CPU/OS has an Execution Disable bit? As far as I know, many modern processors and Operating ...
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3answers
215 views

Why do executables depend on the OS but not on the CPU?

If I write a C program and compile it to an .exe file, the .exe file contains raw machine instructions to the CPU. (I think). If so, how is it possible for me to run the compiled file on any computer ...
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1answer
197 views

How does an optimizing compiler react to a program with nested loops?

Say you have a bunch of nested loops. public void testMethod() { for(int i = 0; i<1203; i++){ //some computation for(int k=2; k<123; k++){ ...
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2answers
176 views

Is it possible to implement a native compiler for a 'managed language' such as Java?

In most cases, it is possible to create both a native compiler and an interpreter for a programming language. The compiler would simply convert the source code to machine code, and the interpreter ...
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6answers
3k views

Is machine language always binary? [duplicate]

I know absolutely nothing in low-level stuff, so this will be a very newbie question. Please excuse my ignorance. Is machine language - the series of numbers to that tell the physical computer ...
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5answers
1k views

Do compiler-writers actually need to 'understand' machine code? [closed]

Might be kind of an odd question. A guy writing a C++ compiler (or whatever non-VM language): Does he need to be able to read/write raw machine language? How does that work? EDIT: I am specifically ...
0
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1answer
290 views

Creating a very basic compiler using Java

I want to try and create my own very basic language, with it's very basic compiler. All using Java. For now, it will only need to enable to 'programmer' to print things to the screen. I had an idea ...
8
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4answers
2k views

Why can't native machine code be easily decompiled?

With bytecode-based virtual machine languages like Java, VB.NET, C#, ActionScript 3.0, etc., you hear sometimes about how easy it is to just go download some decompiler off the Internet, run the ...
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4answers
655 views

How does assembly relate to machine/binary code

How does assembly relate to machine/binary code. For example here is how to print to the screen in mikeOS(a small pure assembly OS), mikeOS it uses NASM to assemble. BITS 16 ORG 32768 ...
0
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1answer
141 views

Fetching instructions from memory

So, I am a noob in assembly language and machine instructions. When the discussion came up as to how funtion calls are implemented at the processor level, someone said that the CALL instruction ...
1
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1answer
159 views

What did machine code for 4-bit architecture look like?

I don't know how a 4-bit instruction could be enough to do something so I read about the Intel 4004 and it says that it used 8-bit instructions and then I can understand how opcode and numbers has ...
3
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3answers
288 views

Is it possible to use GNU GPL for application that has no source?

I mean, it is possible to create application without source code - for example using HEX editor or some debugger that can assembly instructions (actually every decent debugger can). Creating programs ...
1
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1answer
689 views

Do compilers have to be written for each model of CPU?

Do you need to take account of the different processors and their instructions when writing a compiler? Have instructions been standardised? Or what tools and techniques are available to assist with ...
12
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4answers
3k views

How is software for machines such as ATMs or TVs built?

As a beginner programmer I've only worked with programming computer based applications, but a question has been coming to my head very often since I started programming and I can't get it answered ...
18
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9answers
13k views

Resources on learning to program in machine code? [closed]

I'm a student, fresh into programming and loving it, from Java to C++ and down to C. I moved backwards to the barebones and thought to go further down to Assembly. But, to my surprise, a lot of ...
1
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1answer
311 views

Is there any example or resource explaining/showing code from High-level to Low-level to deep down Machine code?

I have been searching for an example over the internet that shows any operation like saving a file or drawing anything in UI or any other sort that shows the implementation from High-leve language ...